Monorail bogies for supporting monorail cars are known in the art, and are used in many monorail car assemblies. The monorail bogies are generally used for supporting the running wheels and guide wheels beneath the monorail cars.
Historically, in order to control pitching movement, single axle monorail bogies utilize stiff dual parallel traction rods that are located on the bogie transverse center line, vertically displaced above each other and above the monorail guidebeam running surface. This arrangement provides both traction restraint and pitching stability of the single axle bogie. However, the traction rods are mounted above the running surface of the monorail guide beam and thus require additional wheel well undercar space (particularly for low floor height applications) to accommodate the traction rods. This increased wheel well results in reduced passenger compartment space thus having the detrimental effect of reducing the potential passenger carrying capacity of the monorail vehicle. In addition, the location of the traction links above the running surface of the monorail guide beam inherently results in an induced pitching moment when traction forces are applied to the bogie. This pitching moment when reacted by the offset traction rods will inherently result in a detrimental pitching angle of the bogie relative to the monorail guide beam, resulting in guide tire scrubbing and increased guide tire wear. In order to minimize this detrimental pitching angle of the bogie, the traction linkage is typically set to a high stiffness which in turn has the detrimental effect of reduced vibration isolation between the bogie and the monorail car body resulting in reduced ride quality.
In light of the above, it can be seen that there is a need in the industry for an improved monorail bogie that includes a traction restraint and pitch control mechanism that permits independent selection of pitch control stiffness and longitudinal stiffness relative to the car body, and that alleviates, at least in part, the deficiencies of the prior art, and improves on the overall functionality of existing monorail bogies.